/*
 * ProGuard -- shrinking, optimization, obfuscation, and preverification of Java bytecode.
 *
 * Copyright (c) 2002-2018 GuardSquare NV
 *
 * This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later
 * version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along with this program; if not, write to the Free
 * Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */
package proguard.classfile.visitor;

import proguard.classfile.*;
import proguard.classfile.attribute.*;
import proguard.classfile.attribute.visitor.ExceptionInfoVisitor;

/**
 * This <code>ExceptionInfoVisitor</code> delegates its visits to another given <code>ExceptionInfoVisitor</code>, but
 * only when the visited exception targets an instruction in the given range of offsets.
 *
 * @author Eric Lafortune
 */
public class ExceptionHandlerFilter implements ExceptionInfoVisitor {
    private final int startOffset;
    private final int endOffset;
    private final ExceptionInfoVisitor exceptionInfoVisitor;

    /**
     * Creates a new ExceptionHandlerFilter.
     * 
     * @param startOffset the start of the instruction offset range.
     * @param endOffset the end of the instruction offset range.
     * @param exceptionInfoVisitor the ExceptionInfoVisitor to which visits will be delegated.
     */
    public ExceptionHandlerFilter(int startOffset, int endOffset, ExceptionInfoVisitor exceptionInfoVisitor) {
        this.startOffset = startOffset;
        this.endOffset = endOffset;
        this.exceptionInfoVisitor = exceptionInfoVisitor;
    }

    // Implementations for ExceptionInfoVisitor.

    public void visitExceptionInfo(Clazz clazz, Method method, CodeAttribute codeAttribute,
        ExceptionInfo exceptionInfo) {
        int handlerPC = exceptionInfo.u2handlerPC;
        if (handlerPC >= startOffset && handlerPC < endOffset) {
            exceptionInfoVisitor.visitExceptionInfo(clazz, method, codeAttribute, exceptionInfo);
        }
    }
}